In a conventional fuel injector for internal combustion engines, described in, e.g., German Patent No. DE 102 57 895 A1, the pipe guiding the fluid, which connects the fluid supply to a valve chamber that is arranged in front of a valve seat in an inflowing nozzle body, is integrated into the valve housing and runs offset in a parallel manner to the housing axis. The valve housing encloses a circular-cylindrical cavity in which a piezoelectric or magnetostrictive actuator is disposed for actuating the valve. The housing wall, which has a circular ring-shaped cross-section, is radially thickened on one side throughout its whole length and is provided with an axial bore in the thickened region, in which the pipe is guided. At the lower end, the pipe is bent at approximately 90°, inserted in a radial opening in the nozzle body that opens out into the valve chamber and is welded or soldered to the nozzle body. At the end facing away from the nozzle body, the pipe is affixed to the intake nipple that forms the fluid supply and permanently connected to the intake nipple.
One conventional piezoelectric actuator for controlling a fuel injector, described in, e.g., German Patent No. DE 103 19 599 A1, is situated in a hollow cylinder developed as a bourdon tube and, with its end faces, lies against an upper and a lower cover plate. The two cover plates are each connected permanently to the hollow cylinder in a form-locking or force-locking manner, for instance, by welding, the hollow cylinder being axially prestressed before the welding. To achieve the spring property of the hollow cylinder, a plurality of equally developed, bone-shaped recesses are stamped into the cylinder wall of the hollow cylinder, which are positioned in a uniformly distributed manner and have the same internal cross sectional area. The actuator is supported with force locking on the two cover plates, and is loaded with pressure by these.